There are many situations in which it is desirable to stack articles, such as business forms, so that they have a vertical orientation, the stack itself being deployed horizontally. This is typically done by conveying the articles, such as shingled signatures, business forms, or individual flexible sheets so that they move horizontally, and then are deflected by a roller, conveyor belt, and/or the like, to move vertically, and then are placed in a stack against a backstop. Typically, the backstop either slides along a horizontal surface, such as shown in U.S. Pat. No. 4,245,832, or is driven (along with a conveyor belt supporting the articles) horizontally continuously at a slow speed allowing the stack to increase in size, such as shown in U.S. Pat. No. 4,361,318. Alternatively, the backstop can be mounted for movement against the bias of a counter-weight, so that as the articles are fed to the stack and the stack size increases, the backstop automatically moves to accommodate that increase against the bias of the counter-weight, as shown in U.S. Pat. No. 3,591,171.
While prior art systems and procedures have allowed effective stacking of numerous types of articles in vertical stacks, there are some articles that have been difficult to effectively stack in this manner. Typically, short, multi-ply business forms (i.e., having a depth of about 3 to 6 inches) have been very difficult to effectively stack in a vertical style high-capacity stacker. As the stack height increases, such forms tend to become "tippy" and tend to fall over or jam, which is not a problem with larger sheets. Prior art systems for horizontally stacking such forms, such as described above, are also not optimum, especially for short, multi-ply business forms.
According to the present invention, a method and apparatus are provided which overcome the problems discussed above with the attempted vertical stacking of short, multi-ply business forms. Also, according to the method and apparatus of the invention, a simple, compact structure, which provides an effective packing force against the forms or like articles when provided in a vertical orientation in a horizontally elongated stack, are provided allowing effective, efficient, and compact stacking of multi-ply business forms or like articles.
According to one aspect of the present invention, a particular conveyor is provided which is utilized in a stacking apparatus according to the invention. The unique conveyor, per se, conveys multi-ply business forms or the like from a generally horizontal orientation to a generally vertical orientation. The conveyor comprises the following elements: A driver roller rotatable about a third axis defined by a shaft. First and second idler rollers rotatable about first and second axes, respectively. First and second generally vertically extending side plates mounting the first through third axes so that they are essentially fixed with respect to each other and are generally horizontal, and so that the idler rollers are both horizontally spaced from the driver roller in a first horizontal direction, and so that the idler rollers are both vertically above the driver roller. Means for mounting the drive roller shaft so that the side plates are pivotal about the third axis. And, at least one conveyor belt extending around the drive roller and first and second idler rollers for engaging business forms and effecting conveyance thereof.
The conveyor may also comprise means for adjusting the location of the third axis along the arc of a circle having a center below and spaced from the drive roller in the first horizontal direction. The at least one conveyor belt preferably comprises a plurality of conveyor belts spaced from each other in a second horizontal direction, transverse to the first horizontal direction. Also, there preferably is provided a cross member extending between the side plates, between the idler rollers, at least one adjustable form depth stop having a stop portion thereof extending horizontally away from the conveyor belt between two of the conveyor belts also being provided, as well as means for adjustably mounting the form depth stop to the cross member. A drive gear may be mounted to the drive roller, so that rotation of the drive gear effects rotation of the drive roller and the conveyor belt. Also, the conveyor is constructed so that its center of gravity is spaced from the third axis in the first horizontal direction, and is significantly above the third axis.
According to another aspect of the present invention, a stacking apparatus is provided, which stacking apparatus may utilize the conveyor described above. The stacking apparatus basically comprises the following elements:
First conveying mean for conveying generally planar articles to be stacked in a first, substantially horizontal direction. Deflecting means for deflecting articles conveyed by the first conveying means toward a generally vertical orientation. A backstop for articles disposed in a generally vertical orientation. Second conveying means for conveying articles generally vertically from the deflecting means into the generally vertical orientation in operative association with the backstop. Means for mounting the second conveying means for pivotal movement about a generally horizontal axis. Third conveying means associated with the backstop for moving the backstop, and a generally vertically oriented articles stack in association therewith, away from the second conveying means in the first direction. First sensing means for sensing pivotal movement of the second conveying means about the generally horizontal axis. And, means for effecting intermittent operation of the third conveying means in response to the sensing means sensing pivotal movement of the second conveying means.
An article depth stop may be mounted adjacent the second conveying means for limiting the generally vertical movement of the articles by the second conveying means, as well as means for adjustably mounting the article depth stop so that the depth stop may be adjusted to accommodate articles of different depths. Also, a plurality of infeed nip wheels may be mounted in operative association with the first conveying means, upstream of the second conveying means in the first direction, for properly positioning articles to be conveyed on the first conveying means.
The first conveying means preferably comprises a plurality of first conveyor belts spaced from each other in a second generally horizontal direction, transverse to the first direction, and the deflecting means includes a deflecting roller over which the first conveyor belts pass. The second conveying means comprises a plurality of second conveyor belts spaced from each other in the second direction passing over a drive roller, and first and second idler rollers. The drive roller has a bottom peripheral surface portion vertically below and upstream of (in the first direction) a top peripheral surface of the deflecting roller. The first idler roller has a bottom peripheral surface vertically above the top peripheral surface of the deflecting roller, and the axis of rotation of the first idler roller is slightly downstream of the axis of rotation of the deflecting roller in the first direction. The drive roller of the second conveying means cooperates with the first idler roller, the first conveyor belts and the deflecting roller to form the deflecting means.
The second conveying means drive roller and the deflecting roller may have intermeshing gears associated therewith so the driving of one of them drives the other. The first conveying means may include a first end roller about which the first conveyor belts are wrapped, disposed at roughly the same vertical position as the deflecting roller and downstream thereof in the first direction. The first end roller is positioned so that the first conveyor belts convey articles in the first direction a short distance after they are stacked in the vertical orientation.
The third conveying means comprises a plurality of third conveyor belts spaced from each other in the second direction, the third conveyor belts preferably wrapped about the first end roller in interleaved relationship with the first conveyor belts. The third conveying means also may comprise a generally horizontal table surface over which the third conveyor belts and the backstop pass.
The means for mounting the second conveying means for pivotal movement about a generally horizontal axis may comprise a shaft connected to the drive roller, and bearing means for mounting the shaft so that it defines a generally horizontal axis about which the second conveying means may pivot. The bearing means may include first and second plates spaced from each other in the second direction and mounting all of the drive roller and first and second idler rollers. Means may also be provided for adjusting the position of the pivot point about which the second conveying means pivots, while still retaining the intermeshing of the gears at the second conveying means drive roller and deflecting roller.
Stop means may be provided for limiting the pivotal movement of the second conveying means away from the backstop so that the center of gravity of the second conveying means is always between the generally horizontal pivot axis thereof and the backstop, so that the weight of the second conveying means biases articles being stacked into their vertical orientation, in operative association with the backstop, providing a packing force. The center of gravity may be adjusted by adjusting the position of the pivot point about which the second conveying means pivots. Also, there may be provided second sensing means mounted in association with the third conveying means at a point thereof remote from the second conveying means, the second sensing means senses the position of the backstop and terminates operation of all three conveying means once the backstop reaches a predetermined position remote from the second conveying means.
According to another aspect of the present invention, a method of stacking a plurality of multi-ply business forms extending in a generally vertical orientation, utilizing a backstop capable of generally horizontal movement, is provided. The method comprises the steps of substantially sequentially (a) conveying the multi-ply business forms having a substantially uniform depth of between about 3 to 6 inches, in sequence, in a first generally horizontal direction, the forms each having a leading edge in the first direction; (b) deflecting the forms, in sequence, so that the leading edges thereof move upwardly; (c) substantially simultaneously with, and subsequent to, step (b), driving the forms so that they move upwardly and assume a vertical orientation, the depths thereof extending generally vertically; and (d) substantially simultaneously with, and subsequent to, step (c) stacking the forms in a horizontally elongated stack, the first form in the stack engaging the backstop.
There preferably is also the further step (e), substantially simultaneously with the steps (c) and (d), of applying the bias of a horizontal force component of a weight against the vertically oriented forms (the weight of the second conveying means, pivoting about the generally horizontal pivot point) against the vertically oriented form so as to facilitate packing of the forms in a stack. Also, there preferably is a step (f) of intermittently, in response to the packing force on the stack reaching a predetermined level (that is, pivoting the second pivot means about its pivot axis away from the backstop) moving the backstop in the first direction of distance sufficient to reduce the packing force on the stack (thereby allowing the second conveying means to pivot back to its initial position). There is also the further step (g) of terminating steps (a) through (f) once the stack of forms has reached approximately a predetermined size. Further, there is a step (h) of limiting upward movement of the forms and the practice of step (b). The position to which upward movement of the forms during the practice of step (b) will be limited may be adjusted prior to initiation of the method, and will depend upon the depth of the forms being acted upon.
According to yet another aspect of the present invention, a method of stacking a plurality of planar articles using a backstop movable in a generally horizontal first direction, so that the articles have a generally vertical orientation, is provided. The method comprises the following steps: (a) Conveying the articles, in sequence, in the first direction, each article having a leading edge in the first direction. (b) Deflecting the articles, in sequence, so that the leading edges thereof move vertically upwardly. (c) Substantially simultaneously with, and subsequent to, step (b), conveying the articles vertically upwardly so that they assume a vertical orientation. (d) Substantially simultaneously with step (c), forming the articles into a horizontally elongated stack while they have a vertical orientation. And, (e) substantially simultaneously with steps (b) and (c), applying a horizontal force component of a weight against the articles in the stack so as to facilitate packing of the articles in the stack, the force component of the weight compressing the articles in the stack while the backstop is held stationary.
It is the primary object of the present invention to provide the simple, effective, and efficient stacking of planar articles, such as short, multi-ply business forms, in a vertical orientation in a horizontally elongated stack. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.